Currently the only renewable budding block is onyx, and adding this would make them renewable and wouldn't feel out of place or break game balance.

The other gemstones can easily be farmed using Crystal Apothecaries in huge amounts and gives players a good reason to leave their base once in a while.
Any specific pro for making the other budding blocks craftable, that I am not seeing, currently?

Also other buddings are available in the last dungeon chest (at least it was in 1.5.7, idk about the later versions)

not having to explore a lot of undergrounds for more blocks, also the ability to just put them all into one place, not more than that I guess.

The only real pro I can think of is basically anti-griefing, but on most servers you've got some of form of that anyways. While this would be nice, I don't see much of a point, and you could always add custom recipes if you really want to.

I have an idea for that. But it will take an update or two :)